The Manchester City manager Roberto Mancini and Mario Balotelli were involved in a confrontation at the club's training ground. Photograph: Eamonn & James Clarke.

Mario Balotelli and Roberto Mancini were involved in a physical confrontation at Manchester City's training ground in an incident believed to have been provoked by a bad tackle on team-mate Scott Sinclair.

Sources said the 22-year-old striker clashed with his manager in front of team-mates at their Carrington base while the squad prepared for their FA Cup third round match against Watford.

The incident took place at the end of training. Photograph: Eamonn & James Clarke.

The source said: "Mancini ran at him – he was furious. He grabbed hold of him and appeared to try and throw him on the floor. It looked like Mario was too strong and he couldn't get him down. Then all the coaches ran in to separate them but Mancini was having none of it. He kept trying to break free and have a go at him again."

City stuff rush over to intervene. Photograph: Eamonn & James Clarke.

The witness said Balotelli went straight to the dressing room and drove away less than 10 minutes later in his camouflaged Bentley – though he stopped briefly outside the gates to sign autographs for waiting fans.

The incident is certain to revive speculation over Balotelli's future, despite Mancini having repeatedly rejected the idea of selling him during the January transfer window.

Mancini told Gazzetta dello Sport at the end of last month: "I think Mario will stay but the future depends mostly on him… The relationship between me and him is always good, even if one day he does something.

The pair were pulled apart by staff. Photograph: Eamonn & James Clarke.

"I love him because for many years we live together. I've seen him grow. But the professional relationship is another thing and I've told Mario what I need from him.

"The time of cheap talk is over. Balotelli is 22 years old and now it's time to be professional. I ask from him seriousness and commitment in training, a more stable private life and correct behaviour on the pitch."

In December 2011 Balotelli and Micah Richards were pulled apart by team-mates at the end of a practice match when Richards accused Balotelli, who was on the same team, of not running hard enough.